Junos Cup 2014
Junos Cup 2014

Tournament 1: South Korea Challenge & Solution - IPTV Transmission over Circuit Cross-Connects (CCC)

[ Edited ]
‎06-12-2014 07:41 AM

Country Flag associated with this challenge: SOUTH KOREA


Author: Antonio Sánchez-Monge


Title: IPTV Transmission over Circuit Cross-Connects (CCC)


Type: Service Provider


Difficulty: High (2 points).


Technical Description: Establish a redundant end-to-end IPTV service from CE1 to CE2. Make sure that in the absence of link/router failures, the single copy of the IPTV stream received by CE2 follows a path that includes PE1.






Challenge Instructions:

For this challenge, you need to start the topology called: “SOUTH KOREA – IPTV Transmission over Circuit Cross-Connects”


You need to start the traffic from CE1, executing the following command:


juniper@CE1> ping interface ge-0/0/1 bypass-routing ttl 10 interval 0.1 source


Leave the traffic running and verify that it’s flowing per this image:




As you can see, CE2 is not receiving traffic, but you shall change that. Here are the conditions:


-       One and only one copy of the original flow sent by CE1 should be forwarded down to CE2

-       That copy of the flow should transit PE1. This must be deterministic and enforced by configuration, not a result of random hashing.

-       If PE1 fails (or its link towards CE1 goes down), the network should converge so that CE2 keeps receiving one copy of the flow (not transiting PE1, this time).

-       The global solution must involve only two set configuration commands. This means that you can pick two devices and execute one set command on each of them, or pick one device and execute two set commands on it.

-       When you provide the solution, you must explain the reasoning behind the choice of the device(s) you configure. Why this/these one(s) and not this/these one(s)?

-       The commands “configure,edit,commit” are needed but they are not counted towards the solution.


In order to verify the redundancy of the solution upon PE1 failure, you are allowed to disable or enable the access interface at PE1.


To solve this challenge submit a brief explanation of your choice(s) of router(s) and why, and then two set commands issued on which router(s).


NOTE: If you have issues connecting to the Junosphere topology please check Junosphere Technical documentation, or request assistance in the Junosphere forum 

Send an email with your proposed solution to junos-cup@juniper.net:

  •  The subject should be “<country-name-of-the-challenge> -  <your-full-name>”. For example: “Brazil – Wolfgang Amadeus Mozart”.
  • In the email body, please include your proposed solution, along with your first and last name and complete mailing address including zip/postal code and your shirt size (S, M, L, XL, XXL, XXXL)


Some additional notes:

  • Feel free to participate in as many challenges as you like, they are open to everyone and the more you participate the better chance of winning!
  • Green Planet Rules: please start one topology at a time, do not run several topologies in parallel and don't forget to stop your active topology when not in use
  • The answers will be read by the organization right after the deadline
  • The challenge instructions are final, and no additional information or tips will be provided before the publication of the solution and the winner list. Please don’t expect a reply from junos-cup@juniper.net.
  • If you feel that your initial solution is wrong or incomplete, you can send up to three messages for the same challenge, but please note that only your last message (received before the deadline) will be read.
  • If you think there is an error in the definition of the challenges, please send us an email with subject (“<country-name> ERROR”); if there is no reply, then it’s likely an intentional condition of the challenge, rather than an error.


You need to configure PE4. Why PE4? Because it is the PIM designated router (DR) at the 10.2.2/24 network. You can check that by executing at PE3 and PE4: show pim interfaces.


This is the configuration that you need to add to PE4:


set routing-options static route qualified-next-hop preference 100

set routing-options static route qualified-next-hop preference 200



Julie Wider
Advocacy Manager
Twitter: @JNetCommunity & @jawider